WO2020058346A1

WO2020058346A1 - Compact multi-band optical measuring unit

Info

Publication number: WO2020058346A1
Application number: PCT/EP2019/075040
Authority: WO
Inventors: Christian LEIRER; Christian Mueller; Ulrich STEEGMÜLLER
Original assignee: Osram Oled Gmbh
Priority date: 2018-09-19
Filing date: 2019-09-18
Publication date: 2020-03-26
Also published as: US11598667B2; US20210348967A1; DE102018123037A1

Abstract

The invention relates to a measuring unit (100) for optically measuring at least one property of a measurement object (M), wherein the measurement unit comprises the following: a) a light-emitting LED component (102), comprising: i) a housing (108), the housing occupying a housing area G; and ii) an LED chip (110) located in the housing, the LED chip comprising a light-emitting light area L; b) a photodetector (104) for detecting light reflected from the measurement object (M), which originates from the LED component, and for outputting a measurement signal, which is dependent on the detection; and c) an integrated circuit (106) for evaluating the measurement signal supplied from the photodetector (104), wherein the LED component (102), the photodetector (104) and the integrated circuit (106) are combined into an integrated unit, characterized by: - a conversion layer (112), arranged in the housing (108) and located over the LED chip (110), which converts light emitted from the LED chip (110) into multi-band light (E); and - the ratio L/G of the light area L to the housing area G being greater than or equal to 0.8.

Description

COMPACT MULTI-VOLUME OPTICAL MEASURING UNIT

Related applications This application claims the priority of the German first application DE 10 2018 123 037.0, which was deposited with the DPMA on September 19, 2018. The content of this first application is hereby fully incorporated by reference into the present application.

Field of the Invention

The present invention relates to a measuring unit for optically measuring at least one property of a measurement object, the measuring unit comprising the following:

a) a light-emitting LED component comprising:

i) a housing, the housing occupying a housing surface; and

ii) an LED chip located in the housing, the LED chip comprising a light-emitting light surface; b) a photodetector for the detection of light reflected from the measurement object, which comes from the LED component, and for the output of a measurement signal dependent on the detection; and

c) an integrated circuit for evaluating the measurement signal supplied by the photodetector,

wherein the LED component, the photodetector and the integrated circuit are combined to form an integrated unit. Background of the Invention

Such a measuring unit is known from document WO 2017/060746 A1. It is used to measure a patient's blood sugar level. For this purpose, it includes a blue LED, an infrared or IR LED, a photodiode and a processor.

The disadvantage of this measuring unit is that the installation space that is required to place it in a watch, a cell phone, in clothing or To integrate in a so-called "wearable" is still relatively large.

In addition, this measuring unit is only for measuring the

5 blood sugar levels suitable.

Summary of the invention

It is an object of the present invention to develop the measuring unit defined above in such a way that it is as small as possible and can be used in a variety of ways.

According to the invention, this object is achieved by a conversion layer 5 arranged in the housing and located above the LED chip, which converts the light emitted by the LED chip into multi-band light, and in that the ratio L / G of the light area L to the housing area G is greater is equal to 0.8.

Due to the multi-band conversion layer, the LED component emits multi-band light. When this multi-volume light is reflected on the measurement object, a whole reflection spectrum results, which can be detected by the photodetector and evaluated by the integrated circuit. The measuring unit according to the invention is therefore suitable for spectroscopy. With this5 spectral analysis, much more information about the measurement object can be obtained than is possible with a monochromatic LED.

Thanks to the small housing size (the housing is hardly larger than 0 the LED chip), the LED component is very compact, so that the measuring unit can be miniaturized accordingly.

By using a conversion layer to generate the multi-volume light, a single LED is sufficient as a light source.5 The space-consuming installation of several separate LEDs is therefore no longer necessary. The LED chip can preferably be set up to emit blue light. Blue light is more energetic than other light colors and therefore best suited for conversion into multi-volume light.

In one embodiment, the LED component and the photo detector can be arranged on the integrated circuit. The measuring unit is particularly compact and space-saving. The distance between the transmitter (LED component) and the photo detector is then minimized. In this case, the LED component and the photodetector are preferably arranged side by side on the integrated circuit.

Alternatively, the measuring unit can further comprise a substrate, and the LED component, the photodetector and the integrated circuit are combined to form an integrated unit via the substrate. This also gives a compact structure, which is also very stable due to the substrate. The LED component, the photodetector and the integrated circuit are then preferably arranged next to one another, the photodetector preferably being arranged between the LED component and the integrated circuit. The photodetector is located near both the LED component and the integrated circuit, which makes it easier to connect the photodetector to the other two components. The LED component, the photodetector and the integrated circuit can be embedded in the substrate. This increases the stability of the measuring unit and saves space. The arrangement is particularly space-saving if the LED component, the photodetector and / or the integrated circuit are flush with the substrate. The substrate preferably consists of a composition based on epoxy resin. Such a composition is inexpensive, with good stability and simple manufacture of the substrate made from it.

It is advantageous if the conversion layer covers the entire light area L. This ensures complete conversion of the light emitted by the LED chip. In particular then no unconverted light emitted by the LED chip can exit the LED component in an undesirable manner.

The measuring unit according to the invention can serve as a spectrometer,

5 with:

the LED component as the light source of the spectrometer, the photodetector as the radiation detector of the spectrometer, which outputs a reflection spectrum of the measurement object as the measurement signal, and

0 of the integrated circuit as an evaluation unit for the reflection spectrum output by the photodetector.

The result is a spectrometer that is extremely compact and yet enables a complex analysis of a measurement object. In addition, the spectrometer manages with a single light source, 5 which nevertheless covers a wide light spectrum.

This enables the integration of the measuring unit in a mobile phone, a wristwatch, another portable device or a piece of clothing or in a so-called "wearable".

0

Definitions

Several technical terms are used in the present application, which are defined in more detail below:

5

A) Multi-volume light

Multi-volume light is light that has a spectrum that has several separate spectral lines. In contrast, monochromatic light has a spectrum with only a single spectral line. Multi-band light differs from broadband light in that broadband light has a continuous spectrum, similar to a black light. Multi-volume light has at least two separate spectral lines. Multi-volume light can also have three or more separate spectral lines.

B) Chip scale package Chip Scale Package (CSP) is a housing of an integrated electronic component, the size of which is comparable to the size of the chip accommodated in the housing. In the present application, one speaks of a CSP package if the ratio C / G of the chip area C to the package area G is greater than or equal to 0.8: C / G> 0.8. If the chip is an LED chip, the light-emitting light area L of the LED chip instead of the chip area C can also be used as a comparison variable. Then it applies to an LED component that it is a CSP component if L / G> 0.8.

Brief description of the figures

Preferred embodiments of the invention will now be described with reference to the drawings. Show:

1 shows a first variant of a measuring unit according to the invention; and

Figure 2 shows a second variant of a measuring unit according to the invention.

Detailed description of preferred embodiments

In the following description, exemplary embodiments of the present invention will be described with reference to the drawings. The drawings are not necessarily to scale, but are only intended to illustrate the respective features schematically.

It should be noted that the features and components described below can be combined with one another, regardless of whether they have been described in connection with a single embodiment. The combination of features in the respective embodiments only serves to illustrate the basic structure and the mode of operation of the claimed device. The measuring units 100, 200 shown in the two figures are used for the optical measurement of at least one property of a measurement object M. The measurement object M can be different objects. The measurement object M can be, for example, a food or also the human skin or a metal or another substance. By using the measurement unit 100, 200, a user can obtain information about the properties of the measurement object M. If, for example, the object is a food, the user can get information about its ingredients by means of the measuring unit. If the object is a substance, information about its composition can be obtained using the measuring unit 100, 200.

The measuring unit 100, 200 obtains information about the measurement object M by throwing light E onto the measurement object M, detecting the light Q reflected by the measurement object and drawing conclusions on the properties of the measurement object M based on its nature.

The measuring unit 100, 200 is a microelectronic assembly. It is intended to be installed as part of an electronic device. The measuring unit 100, 200 is usually no larger than a fingernail.

A first variant 100 of a measuring unit according to the invention will now be described with reference to FIG. 1.

The measuring unit 100 comprises a light-emitting LED component 102, a photodetector 104, and an integrated circuit 106.

In the present example, the LED component 102 and the photodetector 104 are arranged next to one another on the integrated circuit. Both the LED component 102 and the photodetector 104 thus sit with their underside on the integrated circuit 106. More precisely, the LED component 102 and the photodetector 104 on the integrated circuit 106 be fastened. For example, they can be glued there. 1 can also be referred to as a "chip on IC". Accordingly, the LED component 102, the photodetector 104 and

5, the integrated circuit 106 is combined to form an integrated unit.

The light-emitting LED component 102 comprises a housing 108 and an LED chip 110 located in the housing. The housing 108 takes up a base area G. The LED chip 110 comprises a light-emitting light area L. According to the invention, the ratio L / G of the light area L to the housing area G is greater than or equal to 0.8. The LED component 102 is therefore a so-called chip scale package or CSP component. 5 This means that the housing 108 of the LED component 102 is only insignificantly larger than the LED chip 110.

The LED chip 110 preferably comprises a blue LED. That is, the LED chip 110 is configured to emit blue light.

The LED component 102 also has a light conversion layer 112 arranged in the housing and located above the LED chip 110. The conversion layer 112 here covers the entire light area L of the LED chip 110. As a result, all of the blue light emitted by the LED chip 110 is converted. The conversion layer 112 is selected such that it converts the blue light emitted by the LED chip 110 into multi-volume light. Preferably, the conversion layer 112 converts the blue light into multi-band infrared light. The infrared light obtained can have, for example, three spectral lines. The infrared light then preferably consists of three infrared components: a first component in the near infrared range, a second component in the middle infrared range and a third component in the far infrared range. The photodetector 104 serves to detect light Q reflected by the measurement object M. This light Q originally comes from the LED component 102.

The photodetector 104 can output to the integrated circuit 106 a measurement signal which depends on the characteristics of the reflected light Q. The photodetector 104 is set up to perform a spectral decomposition of the reflected light Q. The photodetector 104 can be implemented as a set of photodiodes, photomultipliers or phototransistors.

The integrated circuit 106 is used to evaluate the measurement signal supplied by the photodetector. The integrated circuit 106 can work analog or digital.

A second variant 200 of a measuring unit according to the invention will now be described with reference to FIG. The measuring unit 200 also has an LED component 202, a photodetector 204 and an integrated circuit 206. It differs from the first variant 100 according to FIG. 1 only in the way the three components 202, 204 and 206 are arranged with respect to one another. The other arrangement in the second variant 200 results from a substrate S provided. The LED component 202, the photodetector 204 and the integrated circuit 206 are combined to form an integrated unit via the substrate S. The LED component 202, the photodetector 204 and the integrated circuit 206 are arranged side by side. The photodetector 204 is located between the LED component 202 and the integrated circuit 206. The three components 202, 204 and 206 are embedded in the substrate S. In the example shown, the LED component 202, the photodetector 204 and the integrated circuit 206 are flush with the substrate S.

The substrate S preferably consists of a composition based on epoxy resin. The measuring units 100, 200 according to the invention can in particular be used as spectrometers in a mobile phone, in a wristwatch or in another portable terminal. The way it works is as follows:

We assume that the measuring unit 100, 200 is integrated in a mobile phone. A user of the mobile telephone can then activate the measuring unit 100, 200 and align it with an object M to be measured.

The LED chip 110 then emits blue light, which is converted into multi-volume light E by the conversion layer 112. This multi-band light E then leaves the LED component 102, 202 in the direction of the measurement object M. From there it is reflected back in the direction of the photodetector 104, 204. The photodetector 104, 204 detects the reflection spectrum Q. This is then evaluated by the integrated circuit 106, 206. Depending on the type of

Spectrum allows conclusions to be drawn about the properties of the measurement object M.

Since the LED component 102 emits multiband light, a more informative reflection spectrum is also obtained from the measurement object M. Such a reflection spectrum distributed over an entire wavelength range contains significantly more information about the measurement object M than a reflection signal which is obtained via a monochromatic light source.

REFERENCE SIGN LIST

100, 200 MEASURING UNIT

102, 202 LED COMPONENT

104, 204 PHOTODETECTOR

106 206 INTEGRATED CIRCUIT

108 HOUSING

110 LED CHIP

112 LIGHT CONVERSION LAYER

M MEASURING OBJECT

EMITTED MULTI-BAND LIGHT

Q REFLECTED LIGHT / REFLECTION SPECTRUM

LIGHT AREA OF THE LED CHIP

G BASE OF THE HOUSING

SUBSTRATE

Claims

EXPECTATIONS

1. Measurement unit (100, 200) for optical measurement of at least one property of a measurement object (M), the measurement unit comprising the following:

a) a light-emitting LED component (102, 202) comprising:

i) a housing (108), the housing occupying a housing surface G; and

ii) an LED chip (110) located in the housing, where the LED chip comprises a light-emitting light area L;

b) a photodetector (104, 204) for detecting light reflected by the measurement object (M), which comes from the LED component, and for outputting a measurement signal dependent on the detection; and

c) an integrated circuit (106, 206) for evaluating the measurement signal supplied by the photodetector (104, 204),

wherein the LED device (102, 202), the photodetector

(104, 204) and the integrated circuit (106, 206) are combined to form an integrated unit, characterized:

by means of a conversion layer (112) which is arranged in the housing (108) and is located above the LED chip (110) and which converts the light emitted by the LED chip (110) into multi-volume light (E); and

in that the ratio L / G of the light surface L to the housing surface G is greater than or equal to 0.8.

2. Measuring unit (100, 200) according to claim 1,

wherein the LED chip (110) is configured to emit blue light.

3. Measuring unit (100) according to claim 1 or 2,

wherein the LED component (102) and the photodetector (104) are arranged on the integrated circuit (106).

4. Measuring unit (100) according to claim 3,

wherein the LED component (102) and the photodetector (104) are arranged side by side on the integrated circuit (106).

5

5. Measuring unit (200) according to claim 1 or 2,

wherein the measuring unit further comprises a substrate (S) and the LED component (202), the photodetector (204) and the integrated circuit (206) are combined to form an integrated unit via the substrate.

6. Measuring unit (200) according to claim 5,

the LED component (202), the photodetector (204) and the integrated circuit (206) being arranged next to one another, preferably the photodetector being arranged between the LED component and the integrated circuit.

7. measuring unit (200) according to claim 5 or 6,

0 wherein the LED component, the photodetector and the integrated circuit are embedded in the substrate (S).

8. measuring unit (200) according to claim 7,

the LED component, the photodetector and / or the 5 integrated circuit being flush with the substrate (S).

9. Measuring unit (200) according to one of claims 5 to 8,

wherein the substrate (S) consists of a composition based on epoxy resin.

10. Measuring unit (100, 200) according to one of the preceding claims,

wherein the conversion layer (112) covers the entire light surface L.

11. Measuring unit (100, 200) according to one of the preceding claims, the measuring unit being a spectrometer, with:

the LED component (102, 202) as the light source of the

Spectrometer,

the photodetector (104, 204) as the radiation detector of the spectrometer, which outputs a reflection spectrum of the measurement object as the measurement signal, and

the integrated circuit (106, 206) as an evaluation unit for the reflection spectrum output by the photodetector.

12. Portable terminal, such as a mobile phone or a wristwatch, with a measuring unit (100, 200) according to one of the preceding claims.